Prior art devices have been utilized for heating and dispensing materials, such as for heating a solid material until it melts and then dispensing the material as a liquid. For example, hot glue guns are used for heating an end of a solid glue stick to a transition temperature at which the glue is liquified and then dispensing the melted glue through a dispensing orifice. Typically, a housing is provided having an interior flow path through which the material is pushed as it is heated. Resistance heating elements are commonly used. The resistance heating elements have been mounted to the housing outside of the flow path, and often outside of the housing.
Other devices have utilized induction heating to heat materials for dispensing. A housing is usually provided having an interior flow path through which the material is pushed as it is heated. An electromagnetically heated susceptor is located either directly in or immediately adjacent to the material flow path. Induction coils have been mounted outside of the housing for inducing eddy currents to flow within the susceptors to generate heat for transferring to the materials. Often an external shroud is provided around the induction coil to protect an operator.
A difficulty with prior devices is that once the meltable materials have been melted and dispensed, it is difficult to cease flow of the meltable material without additional and unwanted drips emerging from the nozzle. The additional flow is partially due to a large orifice in the nozzle and to an area of high pressure resulting from compression of the meltable material from the pusher used to force a material towards the heating elements. An additional inconvenience associated with prior devices is that the apparatus may only be used for a limited amount of time before the glue stick must be replaced.